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 Post subject: Re: N64 benchmarks
PostPosted: Sat Dec 15, 2018 12:45 pm 
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I actually want to target 64 kbps or lower, 96 was just the lowest listening test that included musepack.

F-Zero X seems to be a form of 16-bit ADPCM:
https://fzerocentral.org/viewtopic.php?t=14170
https://github.com/jombo23/N64-Tools/tr ... oolUpdated

edit: and apparently it spent 35mb on music alone.


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 Post subject: Re: N64 benchmarks
PostPosted: Sat Dec 15, 2018 1:06 pm 
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Location: Seattle
What's the computational load for a softsynth vs a decoder?


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 Post subject: Re: N64 benchmarks
PostPosted: Sun Dec 16, 2018 3:18 am 
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MIDI playback can be fast, but at least timidity is about 10x slower vs vorbis decoding on x86_64. Lots of official N64 games used MIDI, but it's quite a lot easier to find musicians for normal formats vs MIDI. I'm not otherwise opposed to MIDI or tracker approaches, though finding optimized, liberally licensed decoders and sample banks might also be an issue.


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 Post subject: Re: N64 benchmarks
PostPosted: Sun Dec 16, 2018 12:18 pm 
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cen64 is now able to profile.


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 Post subject: Re: N64 benchmarks
PostPosted: Mon Dec 17, 2018 4:10 am 
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ERP, a commercial N64 dev, mentions on beyond3d that the RDRAM random latency is 64 cpu cycles. Putting it here too to spread the info. That's almost modern-cpu level cost for a cache miss, damn.


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 Post subject: Re: N64 benchmarks
PostPosted: Mon Dec 17, 2018 10:18 am 
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My understanding is that this wasn't just the inherent RDRAM latency, but the total cost of the CPU having to interface with the RAM via the memory controller on the RCP. I also didn't get the impression that it was always exactly 64 cycles; that number might be an average or a worst-case scenario.

But yes, it's been noted that optimizing for size often gives the best speedup with N64 code...


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 Post subject: Re: N64 benchmarks
PostPosted: Mon Dec 17, 2018 11:18 am 
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I had tried that with some of the audio codecs, and -Os was something like 20% slower than -O3.


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 Post subject: Re: N64 benchmarks
PostPosted: Mon Dec 17, 2018 11:41 am 
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Obviously it depends on the code, and presumably the compiler too. I just meant that cache misses are known to be a fairly big deal on N64, and since the cache is not huge, it's something to watch out for.


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 Post subject: Re: N64 benchmarks
PostPosted: Tue Dec 18, 2018 7:15 pm 
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calima wrote:
I had tried that with some of the audio codecs, and -Os was something like 20% slower than -O3.
I didn't try with MIPS, however something that I observed is that gcc often generates smaller code with -O3 than with -Os, at least when compiling for ARM Cortex-M3 devices. That alone may explain the difference.

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 Post subject: Re: N64 benchmarks
PostPosted: Sat Jan 05, 2019 12:23 pm 
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Did a video test, just for fun and to see what the scale would be. I couldn't find any liberally licensed mpeg1, mpeg2, or mpeg4 decoders, so I just did one test with Xvid (which is GPL).

The results are rather astounding. Even though it's the Simple profile, lacking in quality compared to xvid with its full features, it should still look better than mpeg1 and many mpeg2 streams. 98% realtime and quite watchable quality. The color conversion can provably be done by the RSP, and the texture filter supports YUV natively too. All just with C, xvid has no mips optimizations.

At the bitrate used, 247 kbps, add 64 kbps for audio, and that makes 40 kb/s, 2.4 mb/min of video. That's plenty of FMVs.


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 Post subject: Re: N64 benchmarks
PostPosted: Sat Jan 05, 2019 1:25 pm 
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Sorenson Spark and Xvid are codecs in the H.263 family. Their R/D is a step above MPEG-2 but just below H.264. How well does Theora run? It's BSD licensed, and its R/D should be comparable to Xvid.


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 Post subject: Re: N64 benchmarks
PostPosted: Sun Jan 06, 2019 2:48 am 
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Theora is several times slower on x86, so not even worth trying. Its quality is also lower.


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